Solid-liquid energy dissipation system, and helmet using the same
A helmet includes one or more pads on an inside surface of a shell, with the pads including a cushioning material that includes porous particles within a carrier liquid. The surfaces of the pores of the particles are lyophobic, resisting wetting by the carrier liquid. When the carrier liquid is placed under sufficient pressure, for example by an impact against the pad, the carrier liquid is forced into the pores. This causes the system to store and absorb energy within the carrier liquid. The pad may be made of flexible material with a pair of opposed major surface face pieces, with cells full of the liquid and particles extending between the face pieces. The liquid and particles may make up a majority of the volume of the pad, for example being at least 50% of the volume of the pad.
1. A helmet comprising:
a shell; and
a pad within the shell;
wherein the pad includes a shock-absorbing material;
wherein the shock-absorbing material includes:
a carrier liquid; and
solid particles within the liquid; and
wherein the solid particles have pores with pore surfaces that are lyophobic with respect to the carrier liquid.
2. The helmet of claim 1 , wherein each of the particles has homogeneous material content throughout.
3. The helmet of claim 1 , wherein the solid particles each include a lyophobic material coating along the pores.
4. The helmet of claim 3 , wherein the lyophobic material coating is on substantially all of exposed surfaces of the solid particles.
5. The helmet of claim 3 , wherein exposed surface of the particles outside of the pores are lyophilic with respect to the carrier liquid.
6. The helmet of claim 1 , wherein the shell is a hard plastic shell, with the pad attached to an inner surface of the shell.
7. The helmet of claim 1 , wherein the helmet is one of an athletic helmet, a military helmet, or a civilian-use helmet.
8. The helmet of claim 1 , wherein the pad includes multiple cells in which shock-absorbing material is enclosed, with walls between the cells preventing fluid communication between the cells.
9. The helmet of claim 8 , wherein the pad includes a pair of faces defining opposed major surfaces of the pad, with the cells extending between the faces.
10. The helmet of claim 9 , wherein the shock-absorbing material constitutes at least 40% of the combined volume of the faces, the walls, and the shock-absorbing material.
11. The helmet of claim 9 , wherein the walls between the cells are integrally formed with one of the faces as a single piece of material.
12. The helmet of claim 9 , wherein the faces and the walls are all made of the same material, and/or wherein the faces and the walls are all made of flexible material.
13. The helmet of claim 1 , wherein the carrier liquid has a freezing temperature that is −30 degrees C. or lower.
14. The helmet of claim 1 , wherein the carrier liquid has a lower freezing temperature than water.
15. The helmet of claim 1 , wherein the solid particles are made from controlled porosity glass.
16. The helmet of claim 1 , wherein the solid particles have at least 50% of their volume taken up by the pores.
17. The helmet of claim 1 , wherein the pores have a Laplace pressure of from 10 psi to 100 psi.
18. A shock-absorbing pad comprising:
a flexible multicell structure having a plurality of sealed cells; and
a shock-absorbing material in the sealed cells;
wherein the shock-absorbing material includes:
a liquid; and
solid particles within the liquid;
wherein the solid particles have lyophobic pores; and
wherein the sealed cells constitutes at least 60% of the volume of the pad.
19. The shock-absorbing pad of claim 18 , wherein the structure includes walls between the cells preventing fluid communication between the sealed cells.
20. The shock-absorbing pad of claim 19 , wherein the structure includes a pair of faces defining opposed major surfaces of the pad, with the sealed cells extending between the faces.
21. The shock-absorbing pad of claim 20 , wherein the shock-absorbing material constitutes at least 80% of the combined volume of the faces, the walls, and the shock-absorbing material.
22. The shock-absorbing pad of claim 20 , wherein the walls between the sealed cells are integrally formed with one of the faces as a single piece of material.
23. The shock-absorbing pad of claim 20 , wherein the faces and the walls are all made of the same material, and/or wherein the faces and the walls are all made of flexible material.
24. The shock-absorbing pad of claim 18 , wherein the sealed cells are in a tessellated configuration.
25. The shock-absorbing pad of claim 18 , wherein the sealed cells are in a hexagonal configuration.
26. The shock-absorbing pad of claim 18 , wherein the solid particles are made from controlled porosity glass.
27. The shock-absorbing pad of claim 18 , wherein the solid particles have at least 50% of their volume taken up by the pores.
28. The shock-absorbing pad of claim 18 , wherein the pores have a Laplace pressure of from 10 psi to 100 psi.
29. The shock-absorbing pad of claim 18 , wherein the pores have a Laplace pressure of from 10 psi to 50 psi.
30. The shock-absorbing pad of claim 18 , wherein the pores have a Laplace pressure of from 20 psi to 40 psi.
31. The helmet of claim 1 , wherein the pores have a Laplace pressure of from 10 psi to 50 psi.
32. The helmet of claim 1 , wherein the pores have a Laplace pressure of from 20 psi to 40 psi.